Various hand coverings for actively supplying heat to the wearer's hands are known in the art. Such hand coverings are called upon to provide an efficient and safe source of heat while minimizing manufacturing, materials, labor, and end-user cost, and at the same time providing a hand covering that maximizes the dexterity and cold-weather comfort of the wearer. The heretofore known hand coverings are deficient in one or more of these and other aspects.
U.S. Pat. No. 2,792,827 (Gravin) discloses a glove having a liquid impermeable chamber integrally formed with the glove and confronting the back of the hand of a wearer thereof. A chemical is disposed into the chamber and combines with another chamber agent such as water causing an exothermic reaction the heat of which warms the hands of a wearer. Among other disadvantages, however, the glove has a comparatively complex and expensive construction, and charging and discharging the chamber with agent and water is both tedious and time consumptive and could result in unintended spillage induced soilage.
U.S. Pat. No. 4,970,081 (Eisendrath) discloses a hand covering having an integral pocket confronting the back of the palm portion of the hand of a wearer thereof for containing a chemical heating element. The chemical heating element has one cover-layer of water-impermeable material, and another cover-layer of water-permeable material. The heating element is activated by the addition of water through the water-permeable cover-layer, and kept inactive by reversing the heating element within the pocket in such a way that the water-impermeable layer is outwardly facing to prevent exposure to moisture. However, among other disadvantages, the pocket disposed on the back of the palm portion of a wearer's hand eliminates any possibility of directly warming the fingers, which are most subject to heat loss thereby subjecting the wearer to cold-weather discomfort, and the integral glove construction therein shown and described is both comparatively complex and expensive. U.S. Pat. No. 2,555,203 (Ramsey) discloses an archers' glove having a pouch for containing heating element similarly confronting the back of the palm portion of the hand, and is subject to like disadvantages.
U.S. Pat. No. 3,569,666 (Murphy) discloses an electrically-heated mitten that includes a pocket positioned over the back of the wearer's wrist to contain a battery. A flap-fastener for the battery pocket energizes the heating circuit, which includes a resistive metallic heating element in strip form sewn in place in an integral mitten liner adjacent the wearer's fingers. Among other disadvantages, the density and bulk of the wrist portion of the hand covering contributes to a loss of hand coordination. Additionally, the batteries can leak corrosive acids, and in some circumstances, can pose the threat of an undesirable if not harmful electric shock, particularly during wet weather.
U.S. Pat. No. 3,292,628 (Maxwell) discloses a therapeutic glove that includes a resistive heating element coiled between an integral liner and shell. The glove is energized through a line cord from a 110 V source. Among other disadvantages, the user is limited to usage within locations prescribed by the length of the line cord, a life-threatening shock hazard exists particularly where either the covered hand or glove becomes wet, and the therapeutic glove is both comparatively complex and expensive to manufacture.